Precoding Matrix Determining Method for Balanced Beam Coverage
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Solution Overview
Problem
In LTE FDD systems, the increased feedback overhead due to 2D antenna technology results in unbalanced beam coverage performance, particularly because the existing methods reduce spatial resolution and lead to coverage holes when downsampling is used to mitigate feedback overhead.
Innovation Solution
A precoding matrix determining method that applies different column vectors to different polarization antennas, with a terminal determining a precoding matrix and sending corresponding indicators to a base station, allowing for balanced beam coverage by selecting appropriate column vectors and phase compensation factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If downsampling method is used to reduce feedback overhead, then feedback overhead is reduced, but spatial resolution is reduced and coverage holes are caused
Solution Approach 1:
The patent applies different column vectors from the codebook to different polarization antennas instead of using the same downsampled column vector for all antennas. This local differentiation allows each antenna to have optimized beamforming characteristics for its specific polarization direction, maintaining spatial resolution and coverage performance while still using a reduced codebook size.
Solution Approach 2:
The patent segments the beamforming optimization by applying different column vectors to different polarization antennas. Rather than using a single uniform downsampled codebook for all antennas, the system divides the antenna array into polarization groups and applies differentiated codebook selections to each group, thereby maintaining coverage performance while reducing overall feedback overhead.
2Productivity
If 2D antenna technology is applied to improve data throughput rate and edge coverage, then throughput and coverage are improved, but feedback overhead is increased
Solution Approach 1:
The patent changes the parameter selection strategy by using different column vectors (different codebook indices) for different polarization antennas. This parameter differentiation allows the system to maintain the benefits of 2D antenna technology for throughput and coverage while reducing feedback overhead through more efficient codebook utilization and reduced feedback granularity.
Solution Approach 2:
Instead of providing full codebook feedback for all antennas individually, the patent applies partial feedback by selecting column vectors from a reduced codebook for different polarization antennas. This partial action approach maintains essential beamforming performance while significantly reducing the feedback overhead associated with full 2D antenna technology.
Data Source
AI summary
A precoding matrix determining method and apparatus are provided. A terminal determines a precoding matrix, where the precoding matrix includes at least two column vector sets, a column vector associated with any column vector set of the at least two column vector sets exists in the at least two column vector sets, and both the any column vector set and the associated column vector are applied on different polarization antennas; the terminal determines a first precoding matrix indicator (PMI) and a second PMI based on the precoding matrix; and the terminal sends the first PMI and the second PMI to a base station. In this solution, different column vectors are applied to different polarization antennas. Therefore, a prior-art defect of unbalanced beam coverage performance is overcome.